Pressure differential valve



May 7, 1968 R. H. O'KANE PRESSURE DIFFERENTIAL VALVE Filed Feb. 16, 19672 Sheets-Sheet l INVENTOR.

BY W! May 7, 1968 R. H. OKANE PRESSURE DIFFERENTIAL VALVE 2 Sheets-Sheet2 Filed Feb. 16, 1967 PIE:-

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Arrame r5 United States Patent 0 3581332 PRESSURE DHFFERENTHAL VALVERichard H. OKane, 16045 Highway 128, Calistoga, Calif. 94515Continnation-in-part of application Ser. No. 414,272, Nov. 27, 1964.This application Feb. 16, 1967, Ser. No. 616,685

7 Claims. (Cl. 251-30) ABSTRA CT OF THE DESCLGSURE A solenoid operablepressure differential valve having a tubular body with a solenoidwinding extending around a portion of its length, a pair of conduitconnectors communicating with its interior, and magnetic primary andpilot valve mandrels slidably disposed within its interior. When thevalve is in closed condition, the pilot valve mandrel rests against theprimary valve mandrel in a position within the field of magnetic flux ofthe winding and the primary valve mandrel is sealingly interposedbetween the connectors in a position isolated from the field of magneticflux of the winding. In operation, upon activation of the winding, thepilot valve mandrel is moved under the influence of the winding to aposition creating a pressure differential across the primary valvemandrel. This differential functions to move the primary valve mandrelinto the field of magnetic flux of the winding and open the connectorsto fluid communication.

This application is a continuation-in-part of my copending applicationSer. No. 414,272, filed Nov. 27, 1964, and now abandoned, entitled,Auxiliary Lubrication Sys tem and Valve Therefor.

The present invention relates to a pilot controlled fluid actuatedpressure differential valve and, more particularly is directed to such avalve ideally suited for employment in an auxiliary lubrication systemfor an engine having a pressure lubrication system.

In the prior art, various types of pilot controlled fluid actuatedpressure differential valves have been provided. These valves typicallyemploy a main valve comprising a diaphram or slidable valve mandrel anda pilot valve controllably associated with the main valve for activationby a solenoid. The present invention is concerned with such valveswherein the main valve comprises a slidable valve mandrel.

The pilot controlled pressure differential valves in the prior artemploying main valves comprising a slidable valve mandrel suffer severaldisadvantages. One of the primary disadvantages is that the solenoidoperators for these valves are typically required to impart liftingforce to both the pilot and main valve mandrels. As a result, arelatively large solenoid is required. Another disadvantage is that themain valve mandrel does not move completely clear of the flow path it isdesigned to open. This results in the requirement of a rathercomplicated valve housing to permit adequate flow. Still anotherdisadvantage is that the main valve mandrel moves through a relativelyshort stroke and, thus, delay in closing of the mandrel upon creation ofa pressure differential thereacross is extremely limited. Such delay, aswill become apparent from the subsequent discussion, is often desirable.Yet another disadvantage is that the valves chatter due to insufficientpressure differential across the main valve mandrel upon opening of thepilot valve mandrel. These disadvantages are all frequently accompaniedby innumerable other disadvantages which, in large part, result fromtheir presence.

In summary, the present invention comprises a pilot 'ice controlledfluid actuated pressure differential valve wherein the valve functionsare effected by independently slidable main and pilot valve mandrels.The pilot valve mandrel is disposed within a solenoid for selectveactivation thereby to create a pressure differential across the mainvalve mandrel. The main valve mandrel is disposed so that pressuredifferential thereacross effects its initial lifting and, once lifted,the solenoid moves it to a position removed from the llow path designedto be opened by the valve.

The primary object of the invention is to provide a pressuredifferential valve capable of overcoming the aforementioneddisadvantages of the prior art valves.

Another object of the invention is to provide a pressure differentialvalve ideally suited for incorporation into an auxiliary lubricationsystem for an engine having a primary pressure lubrication system.

Other objects and advantages of the invention will become apparent fromthe following detailed description and accompanying drawings wherein:

FIG. 1 is an elevational view, partially in section, diagrammaticallyillustrating the valve of the present invention incorporated into anauxiliary lubrication system for an engine provided with a pressurelubrication system;

FIG. 12 is an elevational view, partially in section, illustrating thevalve of the invention and the internal components thereof;

FIGS. 3 and 4 are sectional views taken on the planes designated bylines 3-3 and 4-4, respectively, of FIG. 2; and

FIGS. 5, 6 and 7 are partial sectional elevational views sequentiallyillustratin the operation of the valve during initial opening, fullopening and closing, respectively.

Referring now specifically to FIG. 1 of the drawings, the numeral 1t)therein designates an engine provided with an oil reservoir pan i2 and aprimary pressure lubrication system adaptccl to withdraw oil from thepan and supply it to components of the engine under pressure. Asschematically illustrated, the lubrication system comprises a withdrawalconduit 14 extending into the pan and leading therefrom to a pump id.The pump 16 discharges through a conduit l8 into a main oil boss 2thprovided on the engine. it is to be understood that the engine ill andprimary lubrication system therefor are of conventional structure andthat oil from the boss 20 is directed to various components of theengine.

FIG. 1 also illustrates an auxiliary lubrication system for the engine10 comprising a closed tank 22 adapted to contain oil under a pressurehead of gas; a solenoid operated pressure differential valve 24connected to the tank 22 to selectively charge and discharge oiltherefrom; and, a conduit 26 extending in fluid communication betweenthe main oil boss 26 and the valve 24. The tank 22 is provided with acheck valve 28 of the automobile tire type through which air may beselectively introduced or discharged. The valve 28 may be employed toestablish a predetermined pressure head in the tank 22 and, when thevalve 24 is open, to purge the primary lubrication system of the engineit A pair of electrical leads fill and 32 are connected to the solenoidwinding of the valve 24, desig' nated by the numeral as, to selectivelyenergize the winding to effect opening of the valve. In the arrangementschematically illustrated, the lead 36 is connected to ground and thelead 32 is connected to a battery 36 which, in turn, is connected toground. The circuit through the leads 3% and 32 is normally maintainedin open condition by a push-button switch 38 interposed in the lead 32.It is through closing of the switch 3% that the solenoid winding 34 isselectively energized. Although the switch as is of the push-buttontype, it is to be understood that the electrical control circuit for thesolenoid winding 34 may be wired for operation by any number ofalternative switching devices. For example, it would be possible to wirethe circuit for operation by the ignition switch of the engine or foroperation responsive to the oil pressure indicator of the engine. Thelatter arrangement is particularly desirable because it assures theauxiliary lubrication system will only be activated when the primary oilpressure system of the engine is in a low pressure condition.

The internal construction of the valve 24 is illustrated in FIGS. 1, 2and 3. From these figures, it can be seen that the valve comprises, as abasic element, a tubular body ill of generally T-shaped configurationclosed at one end by a barrier 42. The body is fabricated of anon-magnetic material and is provided at the distal end thereof oppositethe barrier 42 with an internally threaded portion The T-leg of thebody, designated by the numeral 46, is disposed immediately adjacent theportion 44 and provided with external threads 43 (see PEG. 1) at itsdistal end. Although the threads 48 are illustrated as being received inan opening therefor in the tank 22, it is to be understood that thesethreads may be employed for connecting the leg 45 to any desired fluidconduit. The portion 44 threadably receives an externally threadedconduit coupling fitting 59 having an annular valve seat 52 formed onthe distal end thereof. The portion .4 and and fitting 5% areproportioned so as to dispose the seat 52 in a position extendedslightly across the opening of the leg 46 into the main portion of thebody 40. The end of the fitting 50 opposite the seat 52 is ofconventional coupling configuration and includes an internally threadedpassage (not illustrated) communicating with the opening, designated bythe numeral 54, extending through the fitting. The internally threadedopening of the fitting is designed to receive a mating fitting 56disposed on the end of a conduit, such as the conduit 26 illustrated inFIG. 1.

The main portion of the body 40 includes a first length 58 extendingthrough the solenoid winding 34 and a second length 6% extending betweenthe winding and the distal end of the portion 44. A flux guide ofmagnetic material for the winding 34 is received around the length 58.This guide comprises a pair of opposed sleeves 62 and 64 concentricallyreceived around the length to define a flux gap 65 and a generallyU-shaped member 68 having axially aligned openings 70 and 72 thereinreceived around the sleeves 6t and 62, respectively. Flared outa-butments 74 and 76 formed on the sleeves 21 and 64, respectively, seatagainst the openings in the member 6 8 to control the Width of the gap66. Through provision of this flux guide arrangement, the flux of thesolenoid 34 is concentrated at the gap (ill and straying of the fluxfield laterally to the length as is, at least in large part, prevented.

The main portion of the body 49 has a main or primary valve mandrel 78and a pilot valve mandrel 80 slida'bly received therein. The mandrels 78and 80 are formed of magnetic material and, upon de-energizing of thewinding 34, are normally urged to the closed condition illustrated inFIG. 2 by a compression coil spring 82 interposed between the barrier 42and the end surface of the mandrel 8G opposed to the barrier. Theprimary valve mandrel 78 is of cylindrical exterior configuration andhas a resilient annular valve disc 84 of neoprene or the like receivedin one end thereof, for seating engagement with the valve seat 52. Themandrel 78 also has a pilot conduit 86 fixed thereto and extendingaxially therethrough. The conduit 35 lends support to the valve disc 84and is designed to extend from the valve disc and through the valve seat52 to an appreciable extent during initial lifting of the valve discfrom the seat. As will become apparent from the subsequent discussion,the latter characteristic facilitates the creation of a pressuredifferential across the ends of the pilot conduit 86 during initiallifting of the primary valve mandrel. The end of the conduit 86 oppositethat extending through the valve disc 84 extends laterally of themandrel 73 to define a crown valve seat 88.

The second length 60 is maintained laterally of the flux field of thesolenoid 34 by annular spacer 9t) of nonmagnetic material. The spacer 98is received around the length 6t; and interposed between the leg 46 andsleeve 64. The internally threaded portion 44 of the second length 60 isreinforced by an annular sleeve 92 fixed to and extending around itsouter surface. The sleeve 92 is provided to prevent deformation of theportion 44 upon threading of the fitting 5i thereinto. Employment of thesleeve is desirable, since the entire tubular body 40 is typicallyfabricated of a relatively soft material, such as brass.

The primary valve mandrel 78 is of such a length that, when it is seatedwith the valve seat 52 as illustrated in FIG. 2, it terminates short ofthe first length 53 having the windings 34 therearound. Thus, when soseated, the mandrel 78 is not subjected to the flux influence of thesolenoid winding 34. In addition to having this length characteristic,the mandrel 78 is of a cylindrical cross section sutficient to have apredetermined limited clearance with the interior of the body 40. Thisclearance is selected so that fluid flow around the mandrel 78 will berestricted to a predetermined degree which is greater than the degree towhich flow is restricted through the pilot conduit 86. The area of thepilot conduit 86 is also related to the area of the opening 54 in thevalve seat 52 in a ratio which creates a mechanical advantage duringopening of the valve when the fluid pressure in the leg 46 exceeds thatin the fitting 50. This mechanical advantage in effect means that theforce required to lift the pilot valve mandrel 80 from the crown seat 88is less than that which would be required to lift the primary valvemandrel 78 from the seat 52. It corresponds to the ratio of therespective interior areas of the opening 54 and pilot conduit 80.

The pilot valve mandrel 80 has a resilient valve disc 94 of neoprene orthe like mounted therein for seating engagement with the crown seat 88.The mandrel is proportioned so that, when seated with the crown seat 88,the end thereof opposite the disc 94 is disposed centrally of the lengthof the flux guide gap 66, Thus, when the solenoid winding 34 isenergized, the mandrel 80 is subjected to concentrated flux pullingforces thereby. The pilot valve mandrel St} is also designed tosubstantially eliminate the occurrence of pressure differentialsthereacross. with the exception of a pressure differential created atthe valve disc $4 when it is seated with the crown seat 88. In theexemplary embodiment illustrated, this provision is made by forming thepilot mandrel 80 of hexagonal cross section so that flow therearound issubstantially unrestricted.

The operation of the auxiliary lubrication system and the valve 24incorporated thereinto will now be described with respect to thesequential illustrations of FIGS. 5, 6 and 7. Although the descriptionis keyed to the operation of the valve in the auxiliary lubricationsystem, it should be understood that the valve would operate in acorresponding manner where employed in other fluid systems wherein it issubjected to similar pressure differentials.

Operation When the auxiliary lubrication system is installed asillustrated in FIG. 1 and the solenoid winding 34 is deenergized,running of the engine will initially cause a portion of the lubricatingoil in the main oil boss 20 to be forced into the tank 22. During thisinitial function, the fluid pressure generated by the pump 16 functionsto lift the primary valve mandrel 78 from the seated conditionillustrated in FIG. 2 in check valve-like fashion. The lifting of thevalve mandrel 78, in turn, permits oil to flow into the tank 22 untilthe gas pressure therein equalizes with the oil pressure in the main oilboss 26. Upon the latter occurrence, the pressure around the primaryvalve mandrel 78 is equalized and, thus, the mandrel is forced to theclosed condition illustrated in FIG. 2 by the spring 82. The latterclosing operation is retarded since the pilot valve mandrel 80 is seatedwith the crown seat 88 and, thus, the only way that replacement fluidmay reach the upper side of the primary valve mandrel 78 is through thesmall clearance between the mandrel and the body 40. This delayedclosing operation is illustrated in FIG. 7 and, as will become moreapparent subsequently, is advantageous during repeated operation of thevalve, since it maintains the valve in open condition for a relativelylong period while oil pressure in the engine is building up.

The compressive force of the spring 82 is sufficient to maintain thepilot valve mandrel 80 in seated condition against the crown seat 88during the aforedescribed check valve-like operation of the valve. Thus,equalization of pressure on opposite sides of the primary valve mandrel78 prior to complete opening of the valve during the check valvefunction is prevented.

Upon closing of the primary valve mandrel 78 under the influence of thespring 82, oil is trapped in the tank 22 under a pressure head of gasequal to the normal operating oil pressure of the primary lubricationsystem in the engine 10. This condition is maintained during continuousrunning of the engine and after termination of this running. Thus, evenafter the engine 10 is stopped and oil pressure in the primarylubrication system thereof is depleted, oil in the tank 22 is maintainedunder pressure.

After the engine 10 is stopped, oil under pressure may be supplied tothe primary lubrication system thereof from the tank 22 by energizingthe solenoid winding 34. This function is accomplished by closing theswitch 38 and is typically effected immediately prior to starting of theengine. Energizing of the coil 34 immediately effects movement of thepilot valve mandrel 88 as depicted in FIG. 5. Specifically, the flux ofthe solenoid winding, schematically illustrated by the curved linesleading into the body 40 in FIGS. 5 and 6, pulls the mandrel 88 fromseated engagement with the crown seat 88 to a position centered relativeto the flux gap 66. The direction of movement of the mandrel to thisposition is designated by the arrow line on the mandrel in FIG. 5.

During initial movement of the pilot mandrel 88 responsive to energizingof the solenoid winding 34, the flux force imparted to the mandrelovercomes the force imparted thereto by differential pressure across thecrown seat 83. The latter force is relatively small, however, because ofthe very limited area of the passage in the pilot conduit 86. Thus, thesolenoid winding 34 need only have a relatively small current draw. Itis noted that the flux field of the solenoid winding 34 is external ofthe valve mandrel 78 when the mandrel is engaged with the seat 52 andthat, accordingly, the solenoid is not required to lift the primaryvalve mandrel 78 from the seat 52.

After the pilot valve mandrel 80 is initially lifted to the positionillustrated in FIG. 5 by the solenoid winding 34, the differential inpressure between the upper and lower ends of the pilot conduit 86 causesoil to flow into the conduit, as diagrammatically illustrated by thearrow lines leading thereinto, to equalize the pressure condition in thevalve body 40 above the mandrel '78 with that in the opening 54 belowthe mandrel. Due to the relatively unrestricted flow characteristics ofthe conduit 86, as compared with the flow path around the mandrel 78, acondition is created where the pressure above the mandrel 78 is lessthan that around its lower external portion. The latter pressure isdiagrammatically illustrated by the arrow line leading to this lowerportion from the leg 46.

The pressure differential condition thu created across the mandrel 78functions to lift the mandrel from the seat 52 and into the fluxinfluence of the solenoid winding 34. This lifting function is enhancedby the portion of the conduit 86 extending through the valve seat 52which, in effect, maintains the lower end of the conduit at a lowpressure condition during initial lifting of the mandrel 78. After themandrel 78 is lifted into the flux influence of the solenoid 34, thisinfluence moves the mandrel 78 into a position wherein the crown seat 83abuts with the valve disc 94 of the pilot valve 80. Upon the latteroccurrence, the primary and pilot valve mandrels move in unison, asdesignated by the arrow lines thereon in FIG. 6, to a position whereintheir composite length is centered relative to the flux gap 66. Upon thelatter occurrence, due to the proportioning of the mandrels 78 and 80relative to the valve body 40, the mandrel 7-8 is maintained in aposition completely laterally of the flow path between the interior ofthe leg 46 and the opening 54. It is because of this characteristic thata large unrestricted flow path may be provided while employing a valvebody of simple T-shaped configuration. The curved arrow line in FIG. 6extending between the interior of the leg 46 and the opening 54 isintended to diagrammatical- 1y illustrate the general flow pattern.

After the valve 24 is opened, as illustrated in FIG. 6, and oil iscompletely discharged from the tank 22, deenergizing of the solenoidcoil 34 Will permit the mandrels 78 and 88 to move downwardly under theinfluence of the spring 82. If the primary lubrication system of theengine 18 is under full pressure at this time, the differential inpressure across the mandrel 78 will maintain it in open condition untilthe tank 22 is again filled with oil under pressure. On completion ofthe latter occurrence, the valve 78 will close under the influence ofthe spring 82 in the same manner as it lid after initial charging of thetank. If, for some reason, the primary lubrication system of the engineis not under pressure after full discharge of the tank 22 andde-energizing of the solenoid winding 34, the mandrels 78 and 80 willsimply move to the closed condition illustrated in FIG. 2 under theinfluence of the spring 82. In this event, charging of the tank 22 willbe effected on the next occurrence of operating pressure in the primarylubrication system of the engine. This charging will be effected in amanner identical to the aforedescribed initial charging of the tank 22.

Once the tank is recharged, it is again in condition to be dischargedthrough the aforedescribed sequence of valve operation illustrated inFIGS. 5 and 6. After each discharging, the tank 22 will automaticallyrecharge as described in the foregoing discussion upon the creation ofoperating pressure in the primary lubrication system of the engine bythe pump 16. Thus, Whenever the engine is run after discharging of thetank 22, the auxiltary lubrication system will be returned to acondition preparatory for supplying oil under pressure to the engineprior to starting.

From the foregoing detailed description, it is believed apparent thatthe present invention enables the attainment of the objects initiallyset forth herein. It is to be understood, however, that the invention isnot intended to be limited to the details of the specific embodimentherein illustrated and described. For example, it is anticipated thatthe valve 24 may be inverted from the position illustrated to facilitatemovement of the primary valve mandrel 7'8 under the influence ofgravity, even when a pressure differential does not exist thereacrossupon lifting of the pilot valve mandrel '78 from the seat 8 8.

What is claimed is:

It. A pressure differential valve, comprising:

(a) a substantially rectilinear tubular element comprised of contiguousfirst and second lengths, at least the first of which is formed ofnon-magnetic material;

(b) means closing said first length at the distal end thereof;

(c) a solenoid winding surrounding said first length and terminatingshort of said second length;

(d) first conduit connecting means at the distal end of said secondlength adapted to establish sealed fluid communication between theinterior of said second length and a first fluid conduit externalthereof;

(e) second conduit connecting means in said second length between thedistal end thereof and said first length adapted to establish fluidcommunication between the interior of said second length and a secondfluid conduit external thereof;

(f) a valve seat in said second length intermediate said first andsecond conduit connecting means;

(g) primary valve mandrel means of magnetic material received in saidelement for slidable movement within said first and second lengths, saidprimary mandrel means being:

(1) engageable at one end thereof with said seat to sealingly isolatesaid first conduit connecting means from fluid communication with saidsecond conduit connecting means through said second length;

(2) of a length such that, when said one end is engaged with said valveseat, the end thereof opposite said one end terminates within a portionof said second length disposed between said second conduit connectingmeans and said first length; and,

(3) of a cross section, measured transverse to the length thereof, torestrict fluid flow therearound to said first length from said secondlength to a predetermined degree;

(h) conduit means extending through said primary valve mandrel meansbetween said one end thereof engageable with said seat and the endthereof opposite said one end, said means being:

(1) adapted to establish fluid communication between a first fluidconduit in fluid communication with said first conduit connecting meansand the interior of said first length when said mandrel means is engagedwith said sea-t; and,

(2) of an internal area adapted to restrict fluid flow therethrough to apredetermined degree less than the degree to which fluid flow isrestricted around said mandrel means;

(i) pilot valve mandrel means of magnetic material received in saidelement for slidable movement within said first length, said pilotmandrel means being:

(1) engageable with said conduit means to sealingly isolate said meansfrom fluid communication with said first length; and,

(2) moveably responsive to energizing of said solenoid winding to aposition opening said conduit means to fluid communication with saidfirst length and permitting said primary valve mandrel means to move, atleast partially, into said first length and within the physical confinesof the solenoid winding therearound.

2. A pressure differential valve according to claim 1,

wherein:

(a) said first conduit connecting means comprises an opening in thedistal end of said second length;

(b) said second conduit means comprises a port opening through the sideof said second length; and,

(c) said element and said primary and pilot valve means are soproportioned relative to each other and said port is so orientated as topermit both of said mandrel means to move towards the distal end of saidfirst length to a position wherein said primary mandrel means isdisposed laterally of said port so as to provide an unrestricted flowpath through said second length between said opening and port.

3. A pressure differential valve according to claim 1,

wherein:

(a) said element is formed of an integral tube of substantially uniforminternal diameter over said first and second lengths; and,

(b) said second conduit connecting means comprises a conduit joined tosaid second length to define a T-joint therewith.

4. A pressure differential valve according to claim 1 further comprisingresilient compression means interposed between said means closing saidfirst length and said pilot valve mandrel means to normally urge saidmandrel means into engagement with said conduit means, said compressionmeans being:

(a) of insuflicient strength to prevent said pilot valve mandrel meansfrom moving out of engagement with said conduit means responsive toenergizing of said solenoid winding; and,

(b) of sufiicient strength to urge said primary valve mandrel means,through the application of force thereto through said pilot valvemandrel means, into engagement with said valve seat upon de-energizingof said solenoid winding and equalization of fluid pressure on oppositesides of said primary valve mandrel means.

5. A pressure differential valve according to claim 1 further comprisinga flux guide operatively associated with said solenoid winding to guidethe flux thereof so that maximum pulling force therefrom is impartedcentrally of the length of the winding and wherein the pilot valve meansis proportioned so that the end thereof opposite that engageable withthe conduit means is, upon engage ment of said primary valve mandrelmeans with said seat and engagement of said pilot valve mandrel meanswith said conduit means, disposed substantially centrally of the lengthof said winding.

6. A pressure differential valve according to claim 1 wherein said valveseat is of annular configuration and said conduit means includes anextension adapted, upon engagement of said primary mandrel means withsaid seat, to extend through said seat.

'7. A pressure differential valve according to claim 4 wherein, toestablish a delay in the time required for said primary valve mandrelmeans to move into engagement with said valve seat responsive to saidcompression means:

(a) the cross section of said primary valve mandrel means is suificientto restrict fluid flow past said mandrel means, when said pilot valvemandrel means is engaged with said conduit means, to a degree retardingmovement of said pilot and primary valve mandrel means responsive tosaid resilient compression means; and,

(b) said respective valve mandrel means and said first and secondlengths are so proportioned relative to each other that said primaryvalve mandrel means must move through an elongated path within thetubular element, upon de-energizing of said solenoid winding, to assumeengagement with said valve seat.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 6/ 1960 GreatBritain.

M. CARY NELSON, Primary Examiner. ARNOLD ROSENTHAL, Assistant Examiner.

